There follows a long discussion of the details of the science which you can read here. Then comes the stinger...

It is never a good thing to make poorly justified scientific claims. When it comes to race and IQ, doing so is toxic.

That brings us to the most difficult part of this essay, in which we consider the moral content of Murray’s racial arguments, and the motivation for Harris’s astonishing willingness to showcase them so uncritically. Murray presents himself as coolly rational and scientific as he proceeds to his conclusion of genetically based racial differences: People differ in behavior, groups of people differ in behavior, people differ genetically, groups differ genetically. One way or another, genes are associated with behavior, so of course some group differences in behavior occur because of genes. No big deal. “This is what a dispassionate look at decades of research suggests,” Harris blithely says.

It is a big deal. The conviction that groups of people differ along important behavioral dimensions because of racial differences in their genetic endowment is an idea with a horrific recent history...

Charles Murray's crackpottery is another midden pile of rationalizing shit the Right wallowed in 20 years ago and tracked all over the house.

And Andrew Sullivan is the highly-paid professional Conservative pundit who, to this very day, will go right on claiming that the ineradicable, racist outhouse stink that permeates every surface of Conservatism is actually the fragrant perfume of wild blueberries, weed and freedom.